Many new and existing golf courses have narrowed their fairways and expanded their rough areas on either side of the fairways. Roughs require less care than fairways, so narrowing the fairways allows golf course operators to lower their maintenance costs. For example, irrigation requirements may be reduced if only the fairways are watered. If grasses in the roughs are allowed to grow longer, those non-irrigated areas are less brown. Trees and other aesthetic features may be located in the roughs, because roots and shade can inhibit turf growth in the fairways.
However, golf course roughs still must be maintained regularly using grass mowing machines that can mow the vegetation at an acceptable length and appearance. Equipment for mowing golf course roughs typically includes a traction vehicle carrying three or more rotary cutting decks, each rotary cutting deck mounted on the end of a lift arm extending from the traction vehicle. Carrying the rotary cutting decks with lift arms extending from the front or sides of the traction vehicle is necessary and desirable, instead of towing the rotary cutting decks behind the vehicle, because it is necessary for the mower to provide close trims next to trees, bunkers or other hazards. Each lift arm also may be used to move a rotary cutting deck between a mowing position and a transport position. The mounting devices also should allow for pitch (front to back pivoting) and yaw (side-to-side pivoting) of the rotary cutting decks.
Traction vehicles carrying several rotary cutting decks may travel at speeds of 6 to 8 miles per hour when mowing golf course roughs. The traction vehicle's weight may be in excess of 2000 pounds. Each rotary cutting deck may be subject to shocks from impacts against the ground surface or objects during mowing. To withstand the rigorous mowing conditions, rotary cutting decks typically are made of thick sheet steel, such as 7 gage or 10 gage sheet steel. Each rotary cutting deck may have a diameter between about 18 inches and 27 inches, weigh at least 120 pounds, and may have a cutting blade rotated by a hydraulic or electric motor.
Golf course operators sometimes need to change the height of cut of rotary cutting decks on a rough mower. For example, the height of cut may need to be changed if the mower goes from an intermediate rough with a 1½ to 2 inch height of cut, to a full length rough with a 3 to 4 inch height of cut. The height of cut also may need to be changed if the machine is used to mow rough for tournaments where rough heights can be as long as 6 inches. Additionally, golf course operators may change the height of cut of a rotary cutting deck due to seasonal variations, shade conditions, or different types of grass or vegetation in different rough areas of a golf course.
Rotary cutting deck height of cut adjustment mechanisms may include side plates having a vertically-spaced series of holes, and bolts extending through the holes to secure the deck to the side plates. The deck height may be adjusted by changing the holes in the deck plates and/or the holes in the side plates through which the bolts extend. Other rotary cutting deck height of cut adjustment mechanisms include spacers that may be stacked on several pins that support the deck on a frame, or on casters that are mounted in vertically oriented sleeves. Changing height of cut using the holes or spacers at each of four adjustment points can be cumbersome and time consuming.
U.S. Pat. No. 7,716,907 assigned to Deere & Company of Moline, Ill. relates to a rotary cutting deck height of cut adjustment mechanism for that includes a front pair and a rear pair of height of cut arms, and an axle extending between each pair. Each of the four height of cut arms may be pivoted to support the mower deck at different cutting heights, and each has a notch lock that may be moved between a locked position and an unlocked position at each cutting height. A lever may be used to push each notch lock from an unlocked position to a locked position or pull the notch lock from a locked position to an unlocked position. This height of cut mechanism eliminates the holes or spacers, but the notch locks must be cleaned or maintained periodically to remove debris and loosen the joints, release the lever and clean out the grooves. A rotary cutting deck height of cut adjustment mechanism is needed that is faster and more efficient to adjust cutting heights, reduces maintenance and is low in cost.